Seed & Plant Sources

Ion Exchange - A company in Harper's Ferry, NE Iowa - (800) 291-2143
native wildflowers and seeds - has milkweed plugs/plants you can order
http://ionxchange.com/search.php?search_query=milkweed&x=0&y=0 
http://ionxchange.com

Prairie Moon Nursery - rural Winona County in southeast Minnesota
Monarch Favorites - Nectar Sources and Larval Host Plants
http://www.prairiemoon.com/monarch-favorites/

Monarch Watch Milkweed Market
http://monarchwatch.org/milkweed/market/

Monarch Watch: Monarch Waystation Seed kits
http://www.monarchwatch.org/waystations/seed_kit.html

Xerces.org - Milkweed seed finder - Search for where to get seeds
http://www.xerces.org/milkweed-seed-finder/

Swift Greenhouses, Inc - Supplier for Iowa, listed under Monarch Watch as pesticide free - Look for their name/logo on the back of description labels on plants in garden centers.
http://www.swiftgreenhouses.com/